A wide variety of automobile anti-theft devices are known in the art. As the public demand for approaches to improved security has increased, especially within recent years, the number of these devices has grown proportionately. However, despite the momentum of accelerating technological innovation, such anti-theft systems have not been widely accepted by the public. Being perhaps somewhat complicated in operation or else unmanageable or unwieldy as a practical matter, oftentimes devices for improving automobile security have not been effectively used on an everyday basis by vehicle owners. To be sure, no anti-theft system can be considered indefatigable. All the same, a secure protective system that could be made widely available and one that could be properly and effectively implemented without undue effort, difficulty or inconvenience for the vehicle owner, might serve to provide a positive contribution towards decreasing the prevalence of car theft generally.
An area of particular focus and significance in the field of automotive anti-theft devices concerns the security and protection of car stereo system component units, which oftentimes have a radio receiver and amplifier along with a tape cassette or compact disc player combined in a single unit. The amount of interest directed to this field is readily understandable since, among those who are concerned with high-fidelity audio and who desire having a quality sound system installed inside their cars, ensuring their audio system components against tampering and theft is also an important consideration.
The security problem for car stereos becomes all the more acute, of course, with modern-day high-fidelity systems which, being both expensive and rather easily portable, all too readily may become targets for attracting unwanted attention. Unfortunately, even the best high-fidelity car stereos remain susceptible to the extent that destruction and disassembly of their installations, however strongly bolted or riveted they may have been initially, might be quickly accomplished using relatively simple tools which are commonly available and not subject to interdiction.
As one of the preferred solutions for preventing the theft of car stereos, vehicle owners often request to have these units installed within a protective sleeve or a mounting bracket contained inside the front dashboard. The entire unit can then be simply removed from the bracket, and thus guarded for safe keeping in the personal possession of the owner, or secured for storage away from the visible notice of any casual passerby whenever the car is to be parked along a public thoroughfare or left unattended for some extended period of time. More recently, some of these units have been manufactured with a separably detachable control panel that can be removed from the front surface of the component unit. By detaching the control panel, the owner renders the accessory component unit virtually unusable and inoperable, even while the rest of the unit remains in place unremoved within the dashboard.
Numerous other approaches exist intending to protect against the misappropriation of car stereos, including such various devices as a warning alarm which sounds upon attempted tampering, or a reminder alarm prompting the vehicle owner to remove the unit before leaving the car. The latter type of apparatus is exemplified in Ghazarian (U.S. Pat. No. 4,906,969) disclosing an anti-theft warning system in which a flashing LED light or an audible beeper alarm becomes activated whenever a removable accessory unit is installed in place within the car during the time until the ignition switch is also closed. The warning system in fact requires the motor vehicle owner to remove the accessory unit before leaving the vehicle, in order to deactivate the warning alarm. There are also many prior art systems of the former type, for example the anti-theft device for a removable car stereo unit disclosed by Holzhauer et. al. (U.S. Pat. No. 4,866,416). The Holzhauer system is intended to inactivate the car stereo by means of a small change-over switch that responds to either a control signal from a separate, "pre-armed" burglar alarm system contained somewhere within the motor vehicle, or alternatively to slight deformation of the outer edge of the microswitch due to small amounts of physical pressure such as would occur if the car stereo were improperly removed. There are a large number of other car stereo anti-theft systems having mechanically activated switching means, as for example shown in the disclosure of Knakowski et al. (U.S. Pat. No. 4,679,026). These several devices are all intended as precautions taken to prevent the attempted larceny of perhaps the most vulnerable automotive accessory. Yet, they are nonetheless all inherently limited, having no amount of effectiveness as regards protective security for the entirety of the motor vehicle.
The prior art also includes a number of anti-theft devices specifically for the prevention or deterrence of theft for the motor vehicle only. Some of these involve a mechanically or electrically coded key required in addition to the automobile ignition key for the normal starting or operation of the vehicle. Again, there are a wide variety of these, with a wide array of mechanical and electrical combinations, for example the variably configurable device disclosed by Greenspan (U.S. Pat. No. 3,004,170). However, among all these numerous anti-theft systems, none as yet has the advantages that might be obtained, in terms of overall usefulness and convenience of implementation, by combining integrally within a removable electronic accessory component unit such as a car stereo, a protective system having anti-theft deterrence for the entire motor vehicle,.
Accordingly, it is the primary object of the present invention to provide a more comprehensive and at the same time more conveniently practicable mode of anti-theft protection for the automobile owner who may already have a theft-preventing removable car stereo, but who lacks a similarly effective anti-theft security system to ensure protection of the entire vehicle. By adapting a particular set of anti-theft elements from the electrical system of the vehicle, and incorporating these within the integral components of an anti-theft removable electronic accessory unit, the present invention permits a measure of protection for an entire car similar to that which previously could be obtained only for the accessory unit itself. Furthermore, the present invention provides the motor vehicle owner a means for achieving anti-theft protection which might be less cumbersome or tedious to use on an everyday basis. The very simplicity and accessibility of its implementation adds to the likelihood of a protective anti-theft system having a positive effect.
Another object of the present invention is to frustrate or deter tampering by those attempting to "jump-wire" the car, trying to defeat or to bypass the negative control of the vehicle that ordinarily obtains upon removal of the accessory unit. The connector used for attaching the removable component has a plurality of electrical contact points, of which only one particular pairing might be used to establish the requisite electrical continuity necessary to operate the motor vehicle. Connector contacts the are not actively required in the electronic system of the vehicle are connected to electrical ground. An intruder who tries to "jump-wire" the car may inadvertently cause a short-circuit to occur in the electrical wire leading from the motor vehicle storage battery; this opens a protective circuit-breaking fuse, interposed between the connector unit and the motor vehicle storage battery, thus interrupting the supply of electrical power for the automobile fuel pump, thereby disabling normal operation of the motor vehicle.
The precise configuration of the invention might be altered according to the varying circumstances, and the particular preferences of individual motor vehicle owners, and is therefore adaptable across a wide variety of specific embodiments. However, the general outlines of the invention as demonstrated and disclosed herein may be shown definitively by reference to the accompanying drawings and to the detailed description following.